According to Reuters and A.P. field reports and the New York Times,
the United States support of rebels in Syria is directly benefitting the
Al Nusra Front, which is allied with Al-Qaeda.

In fact, Al Nusra has become the de facto leaders of the entire rebel
movement, international news media accounts indicate. Moaaz Al-Khateeb,
the US designated leader of the Syrian opposition groups has said the
US made a “grave mistake” listing Al-Nusra as a terrorist group. He
called the jihadis the backbone of the rebellion.